Drum type electric clock mechanism



Nov. 15, 1960 Filed June 17, 1957 H. H. HARADA DRUM TYPE ELECTRIC CLOCK MECHANISM 2 Sheets-Sheet 1 Nov` 15, 1960 H. H. HARADA 2,959,914

DRUM TYPE ELECTRIC CLOCK MECHANISM Filed June 17, 1957 2 Sheets-Sheet 2 IN VEN TOR.

Unite rates arent DRUM TYPE ELECTRIC CLOCK MECHANISM Henry H. Harada, Grand Blanc, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed June 17, 1957, Ser. No. 666,115

1 Claim. (Cl. 58-125) This invention relates to clocks and more particularly to drum type electric clock mechanisms.

Electric clocks, especially if intended for use in automobiles, should be simple and rugged to avoid diiiiculties arising from unavoidable shocks and jars met with in such service. Drum type clocks have heretofore been particularly designed for stationary use but it is obvious that such clocks, if mechanically practical for road use, would be particularly advantageous in vehicles as they may be directly and, therefore, quickly read. The necessity for ruggedness and simplicity is still present, obviously, when drum type clocks are considered for vehicular use.

An object of the present invention is to provide an improved drum type electric clock mechanism suitable for use in vehicles. Another object is to provide a drum type electric clock mechanism with a single control means for resetting the drums in either direction independently of or without interfering with the normal operation of means driving the clock. Another object is to provide a drum type clock mechanism in which a solenoid is employed most effectively to secure normal operation of the clock.

A feature of the invention is a clock mechanism driven through an overload yielding clutch permitting resetting of the drums of the clock in either direction by a single control means such as actuated by an exterior rotatable knob. One other feature is a clock mechanism having a resetting element associated therewith in a casing and which is independent of the normal clock operation. Still another feature is a solenoid and armature arrangement in a drum type clock in which arrangement the armature has a recessed face allowing improved attraction between the armature and the core of the solenoid.

The invention will now be more particularly described by reference to the accompanying drawings and thereafter pointed out in the claim.

In the drawings:

Fig. l is an end view, with portions broken away, of a clock in a casing and in which features of the present invention are embodied;

Fig. 2 is a front or elevation view looking in the direction of the arrows 2-2 in Fig. l with the front cover plate removed from the casing and portions of the interior structure broken away better to illustrate the invention;

Fig. 3 is a view similar to that of Fig. l but withv some parts omitted and the clock driving mechanism with parts as positioned dur-ing a different portion of the driving cycle;

Fig. 4 s a partial sectional view, the sectional portions being as seen looking in the direction of the arrows 4-4 in Fig. 2;

Fig. 5 is a sectional view looking in the direction of the arrows 5 5 in Fig. 2; and

Fig. 6 shows structural details as seen looking in the direction of arrows 6--6 in Fig. 4.

Some of the structural features referred to herein are also disclosed in my copending application for United States Letters Patent, Serial No. 626,923 tiled December 7, 1956, now abandoned, and entitled Clock Mechanisms. These features relate to a similar ratchet arrangement for operating the clock, i.e., the means for rotating the drums of the clock, also the clock casing and the circuitry necessary for driving the clock using a current control unit and a battery as the source of power supply. It will be appreciated that the power supply as directly applied to the clock must be such as accurately to provide one electrical impulse per minute and preferably of not less than one-half second nor more than seven seconds duration. With such a power supply available through the use of commercially known devices, the following description pertains and is confined to the structure of the clock per se with which the present invention is concerned.

In the drawings, the invention is shown as embodied in a clock enclosed in a casing 6 provided with a removable front cover 8. This clock is of the jump type in which time is indicated by three coaxial drums i2, i4 and 16. The drum l2 carries the indicia or gures O to 9 on its periphery. The drum i4 bears the figures 0 to 5 and the drum 16 bears the figures l to l2. These three drums are carried on a shaft 2t?, the ends of which are journale'd on the clock frame 22 and casing 6.

A solenoid generally indicated at 24 is mounted inside an inner frame 23 itself enclosed within the casing 6 and this solenoid has a core one end 28 of which extends toward the axis of the drums l2, 14 and i6 to act on an armature plate 30 pivoted at 3l at the rear of the clock and the other end is aiiixed to the inner frame 23. This armature plate is substantially L-shaped with an upwardly extending leg 32 having two forwardly extending brackets 34 andy 36. The bracket 34 pfvotally supports a two- Vngered member or pawl 37 adapted to act on the teeth 3S integral with the hub of a clutch disk 4? mounted coaxially with the drums i2, 14 and 16 on the shaft 2G. The bracket 36 pivotally supports at 42 a lower iinger or pawl 44 also actingk on the teeth 38. The pawls 37 and 44 are made of nylon. A coiled spring `46 has one end fastened to a tab 48 extending from the member 37 and the other end xed to a tab 50 integral with the finger 44. It will he understood that, upon energizing of the solenoid 24 by directing one impulse to the coil of the solenoid 24 per minute and by way of the terminal 25, the armature plate 30 will intermittently be swung upwardly and toward the end 2S of the solenoid core into its position, as shown in Fig. 3, and against a rubber stop 23 on the inner frame 23. When such motion occurs, the clutch disk 40 is held by the lower finger or pawl 4d preventing its rotation. Simultaneously with this action the intermediate finger or pawl 56 of the member 37 slides along a tooth 38 and engages the next tooth preparatory toy rotating the clock drum l2. When the solenoid 24 is deenergized, the armature plate 30 drops down under the influence of gravity and a suitable power spring d5 and, as a result, the intermediate uger 56 rotates the clutch disk 40 in a clockwise direction as viewed in Fig. l. This downward movement of the armature plate 3d constitutes one jump for the clock, and over-running or rotating of clutch disk 40 more than one tooth at a time is prevented by the upper or stop iinger of pawl 37. it will be noted that the clutch disk 4h is provided with ten teeth 38 and, accordingly, if the solenoid 24 is energized once a minute, the clutch disk 40 will be given a full rotation in ten minutes. Reading of the clock is through an opening or window 51 (see dotanddash lines in Fig. 2) formed in a frontal plate 53 supported on the frame Z2 and cover 8.

Ratchet mechanisms, which are solenoid operated for rotating electric clocks of this general type, have heretofore been used and a representative type is disclosed in 3 the United States Patent 2,244,601 granted June 3, 1941, in the name of J. E. Barth. Insofar as the present invention is concerned, other types of ratchet mechanisms may be employed as a primary driving means normally to rotate the clock drums but the type disclosed is preferred.

The clutch disk 40 has two coaxial portions one of which constitutes a hub with ten peripheral ratchet teeth 38 formed integral therewith and the other portion is in the form of a disk and has three spaced knobs 66 on the side opposite the teeth 38. Each of these knobs is arranged to extend into one of ten radial recesses formed in the clock drum 12. Such recesses are shown at 70 in Figs. 2, 3, 4 and 5.

Coaxial with and rotatable on the shaft 20 is a sleeve 72, one end portion of which bears a gear 74 integral therewith. The other end of the sleeve carries two parallel projections 76 and 78 which extend into recesses 80 and 82 formed in the drum 12. The sleeve 72 may be `termed a secondary driving means for the drums. The clutch disk 40 is slidable axially on the sleeve 72 and the three knobs 66 with sloping sides are urged into three of the recesses 70 by the action of a coil spring 86 held in compression between the gear 74 and the clutch disk. An annular shoulder on the latter constitutes a stop limiting the maximum extent with which the knobs 66 may enter the recesses 70.

A knurled clock resetting knob 88 is located at the front of the instrument and its shaft 89 carries a gear 91 which is adapted to engage the gear 74. Positive rotation of the drum 12 by means of manual actuation of the knob 88 independently of the normal power operation of the clutch disk 40 to reset the clock is possible because the spring 86 will yield. This yielding is due to the knobs 66 being cammed out from the recesses 70 as the sleeve 72 continues its normal rotation necessary for driving the drum. The clutch disk 40 and spring 86 arrangement comprises what is termed here as an overload yielding clutch. The manual eifort overloads the clutch to effect resetting.

It will be understood that when the drum 12 has r0- tated ten jumps or one complete revolution, motion will be transmitted from that drum to the drum 14 so that the next digit thereon will appear to the observer through the slot 51. When the drum 12 has rotated suiciently to show the digit 5, the next jump of rotation will show and the drum 16 will be rotated suiiiciently to show the next hour figure, i.e., it will indicate the digit 1 after the gure 12 has been indicated. The transfer of motion from drum 12 to drum 14 and then to drum 16 may be carried out by a conventional mechanism and a suitable type mechanism for this purpose is disclosed in the United States Patent 2,343,613, granted March 7, 1944, in the name of Edwin M. Goldsmith, Jr. A number of such transfer mechanisms is available on the market and suitable for operation with the invention disclosed herein.

In operation of the clock, the accurately timed impulses of current, insulated by a grommet 21, are supplied through the terminal 25 to actuate the solenoid coil 102 and the casing 6 forms a ground connection for the other end of the coil. The resultant intermittent action of the power spring 45 causes the clutch disk 40 to rotate an amount dependent upon the length of one ratchet tooth 38 each time the solenoid 24 is deenergized. When the clutch disk 40 has rotated through ten teeth or jumps or one complete revolution, it has carried the drum 12 with it to the same extent because of the normal and yielding clutch engagement of the disk knobs 66 therewith. The normal operation of the clock has been more fully set forth previously in the specification but it should be noted that in such normal operation the exterior knob 88 could rotate as the drum 12 rotates but, obviously, this may be objectionable and, therefore, a spring 94 is provided urging the shaft 89 axially to disengage the gear 91 from the gear 74. In normal operation of the clock the knob 88 does not turn. When the clock is to reset, the knob 88 is pushed to cause the gears to engage and suicient manually applied torque is used to overload the clutch. The knob 88 and the drums may be turned in either direction.

The leg or face plate 32 of the armature plate 30 is centrally recessed as at 32' (Fig. 1) to aiord a close approach of the plate to the end of the solenoid coil. This results in a more eifective action by the solenoid in normally operating the clock. Obviously, the recess 32 could be an opening with the same result, i.e., the plate 32 should be so made of magnetic material as closely to conform with the flat end of the coil and thereby increase the magnetic properties of the solenoid. The recess 32 or space in the armature 30 receives the end of the core 28 cutting down the air gap.

From the above, it will be seen that applicant has provided a clock mechanism which may be reset in either direction, which is strong in carrying out its normal operation cycles, and which is simple and rugged in construction.

I claim:

A clock mechanism including a frontal plate with a window, a multiplicity of coaxial drums bearing indicia on their peripheries arranged to be viewed through said window, a solenoid with a core and coil having a common axis extending at an angle with the axis of said drums, a spring, primary driving means and secondary driving means for said drums, said primary driving means including a clutch disk biased by said spring into normal, yielding and coaxial engagement with one of said drums and including also a solenoid actuated ratchet arrangement, said clutch disk having a 'hub with ratchet teeth thereon, said solenoid and ratchet arrangement being adapted to engage said hub teeth normally to rotate said clutch disk and one drum as a unit intermittently and in one direction, said secondary driving means including means positively engaging said one drum for rotation therewith and upon which said clutch disk is journaled, and resetting means including a manually rotatable knob accessible to the operator and disengageable gearing actuatable by said knob for positively rotating said secondary driving means and one drum in either direction despite the torque normally and yieldingly supplied to said drum by said solenoid and ratchet arrangement.

References Cited in the file of this patent UNITED STATES PATENTS 1,091,771 Schurmann Mar. 31, 1914 1,414,964 Lossing May 2, 1922 1,898,660 Gatesy Feb. 21, 1933 2,272,242 Frischknecht Feb. 10, 1942 2,456,122 Guilden Dec. 14, 1948 2,587,277 Bergman Feb. 26, 1952 2,650,957 Cohen Sept. 1, 1953 2,779,154 Maurer Jan. 29, 1957 2,790,300 Lux Apr. 30, 1957 

